A pinch clamp to restrict flow in a flexible tube or hose is provided. The pinch clamp includes two elongated pinching members that are pivotally connected at one end with a threaded tightening member at the other end for selectively securing the pinching members in a closed position when the pinching members are pivoted toward each other. The inner cooperating faces of elongated pinching members have flat cooperating surfaces for engaging the flexible tube or hose.